Poly(organotin)mercaptide polymers and resins stabilized therewith



United States Patent 3,518,223 POLY(ORGANOTIN)MERCAPTIDE POLYMERS ANDRESINS STABILIZED THEREWITH Joseph Fath and Donald L. Deardorlf,Barrington, R.I.,

assignors, by mesne assignments, to Teknor Apex Company, a corporationof Delaware No Drawing. Filed July 26, 1966, Ser. No. 568,061 Int. Cl.C08f 45/62 US. Cl. 26045.75 8 Claims ABSTRACT OF THE DISCLOSUREPolyvinyl halide resins are stabilized against thermal discoloration anddegradation by incorporating as a stabilizer poly(dialkyltin )mercaptidepolymer.

This invention relates to novel organotin bearing condensation polymersuseful in the stabilization of resins derived from ethylenicallyunsaturated compounds and to the resin compositions produced by theincorporation of this stabilizer. The organotin bearing condensationpolymers may be differently described as poly(dialkyltin) mercaptidepolymers.

It is well known that polyvinyl chloride, its copolymers, and many othervinyl halide based resins are subject to degradation and discolorationat the elevated temperatures needed for processing, and even undernormal conditions and usage beyond the manufacturing stage. A largevariety of compounds are now known which are effective in preventingthis discoloration for relatively long periods of time. Among thesestabilizer compounds, organotin derivatives have proven to be some ofthe most desirable. Examples of these organotin derivatives are found inus. Pats. 2,648,650 and 2,801,258. These patents disclose processes bywhich diubutyltin mercaptides are derived from the reaction of simplemercaptans, such as lauryl mercaptan, or simple mercaptoesters, with anorganotin compound.

The present invention provides an improved stabilizing composition foruse in the stabilization of polyvinyl halide resins. By polyvinyl halideresins, we mean to include such resins as are obtained by polymerizingsuch monomers as vinyl chloride, vinyl fluoride, vinylidene chloride,trifluoroethylene, tetrafluoroethylene, either alone or withcopolymerizable monomers such as vinyl acetate, ethyl acrylate,acrylonitrile, etc.

The stabilizing composition is a condensation polymer containingrepeating groups of the general structural formula where each R is ahydrocarbon moiety containing up to 12 carbon atoms and can be alkyl,cycloalkyl, aryl, or alkaryl and A is a polyfunctional organic radicalhaving certain further characteristics hereinafter described in greaterdetail. It will suffice at this point to state that the polyfunctionalorganic radical A is derived from a polyol containing more than twohydroxy groups wherein more than one has been esterified with a mercaptoacid and all or part of the remaining have been esterified with a sulfurfree organic acid. The resulting condensation polymer can therefore bewidely varied in its structure to permit it to possess valuableproperties, such as controlled lubricity and fusion time, and oxidativeand light stability. At the same time, the polymeric nature of thesestructures provides relatively lower volatility and odor, both highlydesirable characteristics, especially during processing of thestabilizer compounds. Moreover, the

ice

stabilizers of the present invention exhibit excellent thermal stabilitywhen compounded, processed, etc.

From the foregoing description of the invention, it will have becomeapparent that a major object of the invention is to provide improved tincontaining stabilizing compositions for use in polyvinyl halide resinsto prevent or retard thermal degradation of such resins.

Another and more specific object of the invention is to provide animproved stabilizer composition for polyvinyl halide polymers andcopolymers, which composition contains active organotin groups condensedwith novel polyfunctional mercaptoesters.

Another object of the invention is to provide, as a stabilizer ofpolyvinyl halide resins and polyvinyl halide copolymers, apoly(dialkyltin) mercaptide condensation polymer which possesses apolyfunctionality allowing numerous variations in the structure of thestabilizers so as to impart certain desirable properties, while fullyretaining the thermal stability characteristic commonly attributed tothe presence of the organotin group.

An additional object of the invention is to provide a novel compositionof matter useful as an intermediate in the preparation of highlyeffective stabilizing materials for stabilizing resins derived fromvinyl halides.

A further object of the invention is to provide an organotin-containingstabilizing composition for vinyl halide resins, which composition isgenerally less volatile than the organotin type stabilizers heretoforeprovided.

Additional objects and advantages will become apparent upon reading thefollowing detailed description of the invention, and referring to theappended examples of itsipractice.

The condensation polymers of the present invention are prepared byreacting an organotin compound, such as a dialkyl organotin oxide, or asalt thereof, with certain polyfunctional sulfur bearing compounds whichare broadly designated as (polymercapto) esters. The esters can best bedefined by their mode of derivation. First, they are derived frompolyhydric alcohols containing more than two hydroxyl groups. Thesealcohols are esterified with mercapto acids containing a sulfhydryl anda carboxylic acid group. In the esterification reaction, at least one ofthe hydroxyl groups are not so esterified. The hydroxyl groups notesterified with mercapto acid can then be esterified with a selectedcarboxylic acid, or may in whole or in part be left essentiallyunesterified. The esters thus formed may be broadly represented by thestructure ')n (Formula 1) where n is a number generally of from one to,and including, six, (preferably 1 to 4), X is a substituted acylradical, and Y is a poly substituted hydrocarbon moiety (preferablycontaining up to 12 carbon atoms) in which R is selected from the groupconsisting of hydrogen, and acyl radicals. Thus, the mercaptoesters canbe either mixed esters or partial esters, containing in either casesulfhydryl groups for subsequent condensation with organotin compounds.

The (polymercapto) esters impart great versatility to the organotinbearing condensation polymers made therefrom since the non-sulfurbearing moiety of the (polymercapto) esters can give selected compoundsvarying widely in process characteristics, or possibly even containingresidues which promote light stabilizing characteristics, improvelubricity, etc.

After formation of the complex esters, they are reacted with anorganotin compound to form condensation polymers which are thestabilizing compounds of the invention. The stabilizing compounds arethen incorporated in the vinyl resins which they are to stabilize toprovide improved, highly stabilized resinous compositions.

Since, as has been indicated, the stabilizer compositions of theinvention are formed by the reaction of organotin compounds with certain(polymercapto) esters, the latter compounds will initially be describedin detail. These (polymercapto) esters are mixed esters and are believedto be novel compositions of matter, and their polyfunctionality plays animportant role in the achievement of the objects of this invention. Theterm polyfunctionality is here intended to connote the presence both ofa plurality of sulfhydryl groups, permitting subsequent condensationwith the organotin compounds, and also at least one hydroxyl group,partially or wholly esterified.

The described polyfunctionality is achieved in preparing the(polymercapto) esters by reacting polyhydric alcohols containing morethan two hydroxyl groups with mercapto acids containing a sulfhydrylgroup as well as a carboxylic acid group. The polyhydric alcohols usedare preferably aliphatic polyols, containing from about 3 to aboutcarbon atoms. Examples of suitable alcohols which can be employed aretrimethylolpropane, pentaethythritol, di-pentaerythritol,trimethylolethane, glycerine, 1,2,6-hexanetriol, sorbitol,1,3,5-pentanetriol, 1,5,8- octanetriol, 4-ethyl-1,4,8-octanetriol and 3butyl-1,2',6- heptanetriol. The mercapto acids used are preferablyaliphatic compounds, and are most preferably mercaptoalkanoic acidscontaining from about 1 to about 6carbon atoms. Examples of suitablemercapto acids for'use in the reaction are mercaptoacetic acid(thioglycolic acid), 3-mercaptopropionic acid, and 4-mercaptobutyricacid.

In carrying out the esterification reaction to producethe describedpolyfunctional mercaptoester, it is essential that the number ofhydroxyl groups furnished bythe polyol molecule exceed that of thenumber of carboxylic groups furnished by the mercapto acid. In this waythe unreacted hydroxyl groups can be reserved for the'purpose oftailoring the properties of the mercaptoester, either by .not furtherreacting the reserved hydroxyl groups at all, or by esterifying them, orsome of them, with selected carboxylic acids. Thus, for example, ahydroxyl not esterified by the mercapto acids can, if desired, beesterified by such carboxylic acids as pelargonic acid, 2-ethylhexanoicacid, lauric acid, coconut fatty acids, butyric acid, benzoic acid,para-toluic acid, paratertiary butylbenzoic acid, salicyclic,iso-decanoic acid, stearic acid, and decanoic acid. The reactionproducts of the esterification reaction will constitute equilibriummixtures which are subsequently suitable for further condensation toproduce the tin bearing polymers.

It can readily be seen that the presence of non-sulfur bearingfunctional groups permits a wide variety of compounds to be produced,and their properties and characteristics to be selectively controlled soas to permit the stabilizers to accomplish certain functions whenincorporated in the resinous materials to be stabilized. Thus, forinstance, by varying the chain length of the carboxylic acid used toesterify the reserve hydroxyl groups, and by using carboxylic acids of afatty nature, an ultimate stabilizing composition can be produced thathas a high degree of lubricity.

The final complex mercaptoesters thus contemplated for subsequentreaction with organotin compounds to produce the condensation polymerstabilizing compositions of the invention can be represented by thestructural Formula 1 HSXO--YOXSH where n is a number from 1 to 6, X is asubstituted acyl radical, and is preferably derived from an alkanoicacid containing from about 1 to about 6 carbon atoms, and Y is a polysubstituted hydrocarbon moiety preferably con taining up to 12 carbonatoms and in which R is selected from the group consisting of hydrogen,and acyl radicals. Examples of esters of this type are:

trimethylolpropane monopelargonate di(thioglycolate) trimethylolpropanemonopelargonate di(3-mercaptopropionate) trimethylolpropanemonopelargonate di(4-mercaptobutyrate) pentaerythritol monopelargonatedi(thioglycolate) pentaerythritol monopelargonatedi(3-mercaptopropionate) glycerol monohexanoate di(thioglycolate)trimethylolpropane monobutyrate di(thioglycolate) 1,2,6-hexanetrioldi(thioglycolate) sorbitol monobutyrate monobenzoatedi(4-mercaptobutyrate) pentaerythritol monopelargonatedi(4mercaptobutyrate) pentaerythritol di(pelargonate) di(thioglycolate)pentaerythritol monopelargonate monobenzoate di(thioglycolate)pentaerythritol monopelargonate monosalicylate di(thioglycolate)glycerol monopelargonate di(thioglycolate) The mercaptoesters can beprepared by conventional esterification procedures. In the examples ofester preparation hereinafter appearing, an appropriate polyhydricalcohol and the desired acids are reacted by heating them together inthe presence of an inert organic solvent. The water produced in thereaction is continuously removed and the reaction is continued until allof the water is removed. The reaction may be catalyzed with strong acidssuch as sulfuric acid, p-toluene sulfonic acid and methanesulfonic acid.The (polymercapto) esters may be recovered by removing solvent andexcess acids with heating and under reduced pressure, and they may befurther reacted in situ as hereinafter described to give the desiredpoly(tinmercaptide) derivative.

The complex mercaptoesters are reacted with organotin compounds to formcondensation polymers which we have determined to possess great value asstabilizers for polymers derived from vinyl halide resins. The preferredorganotin compounds used in the preparation of the stabilizers aredialkyltin oxides and most preferably, those in which the alkylsubstituents contain from about 4 to about 8 carbon atoms. In additionto the dialkyltin oxides, dialkyltin hydroxides, dialkyltin halides andacetates can also be utilized. The condensation reaction occurringbetween the mercaptoesters and dialkyltin oxide compounds can beillustrated in a broad and general sense by the following equation:

where A is the group (XO-Y-OX) (OR)n of Formula 1, m is a positiveinteger determined by the stoichiometry of the reactants employed andthe chain length of the condensation polymer produced, and each R is analkyl radical, preferably of 4 to 8 carbon atoms.

From the foregoing equation, it will be seen that the product of thereaction is a true condensation polymer, the structure and compositionof which are specifically defined by the stoichiometry and multiplicityof the reaction system. It can thus be seen that if approximately equalmolar ratios of the two bifunctional reactants are used, as indicated inEquation 1, very high molecular weight condensation polymers can beproduced. While being functional or operative insofar as the practice ofthis invention is concerned, such high molecular weight substances oftenhave the disadavntage of being extremely viscous, or semi-solid, andhaving a nondefinitive termination. For

this reason, it is frequently desirable and advantageous to terminatethe condensation polymers in a manner analogous to common practice inplasticizer technology. The termination can be accomplished by the useof monofunctional sulfur-bearing or carboxylic acid groups as indicatedin Equations 2 and 3:

i mHSASH (m DSInO where A is the group XOYOX hereinbefore defined inreference to Equation 1, R and 111 have the meanings hereinbeforeestablished, X is selected from the group consisting of S and and R" isselected from the group consisting of alkyl, aryl, alkylene carboxyalkylor alkylene carboxyalkoxyaryl radicals. By the use of such terminationprocedure, additional species of condensation polymers can be generatedwhich have lower molecular weights by virtue of the termination, andwhich also have lower viscosities, and are more readily controllableduring actual production. In addition to the reduction in the molecularweight of the polymers produced, the use of the termination procedurepermits further variation in the properties and performancecharacteristics of the condensation polymers since a variety ofterminating agents can be utilized. Terminating agents may, for example,be chosen from carboxylic acid, alkyl or aryl mercaptans and a number ofmonofunctional mercaptoesters. Preferred terminating agents include, butare not limited to, lauryl mercaptan, C C n-alkyl mercaptans, tetradecylmercaptans, stearyl mercaptan, butyl thioglycolate, phenoxyethylthioglycolate, isooctyl thioglycolate, hexyl mercaptopropionate, phenoxyethyl mercaptopropionate, benzyl mercaptopropionate, laurylthioglycolate, pelargonic acid, benzoic acid, and other acids enumeratedherein for use in the esterification procedure to produce themercaptoesters.

It is to be noted that while the terminated condensation polymers arethe preferred stabilizing compositions of the invention due to theadditional processing advantages they impart and incur, the invention isnot limited to such terminated polymers, but also encompasses thebroader concept of condensation polymers which are not terminated, andhave a very wide range of relatively higher molecular weights.

Among the preferred stabilizing compositions of the invention are thosederived from dibutyltin oxide, pentaerythritol, pelargonic acid andmercaptopropionic acid, such as, for example, poly(di-butyltin)[pentaerythritol (pelargonate) (mercaptopropionate)](phenoxyethylmercaptopropionate) The stabilizing agents are prepared byheating the (polymercapto) ester and an appropriate terminating agent(if one is used as per reactions (2) and (3)) with the selectedorganotin compound. The reaction can be conveniently carried out in thepresence of an inert organic solvent which facilitates the removal. ofwater formed during the reaction. The reaction may be, but is notnecessarily, conducted in the presence of acid catalysts. The poly(mercaptide) condensation polymer products are recovered by filtrationof any solid material which may be present and removal of the solvent byheating under reduced pressure. As has previously been indicated, the(polymercapto) ester may be converted in situ to the condensationpolymer stabilizing agent, that is, all the reactions can be performedin a single reaction vessel.

The following examples are presented in order to illustrate the mannerin which the novel (polymercapto) esters of the invention are prepared,and to further illustrate the manner in which these esters are convertedto stabilizing compositions useful in the stabilization of resins.

EXAMPLE 1 Preparation of trimethylolpropane monopelargonatedi(thioglycolate) Trimethylolpropane, 268 grams, and pelargonic acid,316 grams, were condensed in the presence of refluxing benzene at 180 C.until the theoretical amount of water of condensation was removed.Mercaptoacetic acid, 470 grams, was added and the mixture refluxed at C.When removal of water of condensation was complete, benzene and excessacids were removed by vacuum distillation. The product had a specificgravity of 1.110 at 25 C., color of 30 APHA, viscosity at 25 C. of 71.6cs. and was found to contain 15.1 weight percent mercaptan sulfur.

EXAMPLE 2 Preparation of pentaerythritol monohydroxy monopelargonatedi(thioglycolate) A mixture of 15 8 grams technical gradepentaerythritol (containing 88 percent by weight mono and 12 percentdipentaerythritol), 184 grams thioglycolic acid and 158 grams pelargonicacid was heated in the presence of refluxing benzene until all water ofcondensation was removed. Volatile components were removed under reducedpressure to give an oil product having a specific gravity of 1.083 at 25C., viscosity of 77.2 cs. at 25 C., color of 70 APHA and containing 14.6percent by weight mercaptan sulfur.

EXAMPLE 3 Preparation of trimethylolpropane monopelargonatedi(mercaptopropionate) A mixture of 268 grams trimethylolpropane and 316grams pelargonic acid was heated five hours at 180 C. in the presence ofrefluxing benzene. Mercaptopropionic acid, 475 grams, was added andreflux continued at C. until the theoretical amount of water ofcondensation was collected. Benzene and excess acids were removed underreduced pressure to leave 833 grams oil product containing 13.8 percentby weight mercaptan sulfur. Specific gravity 25 C.=1.0830; viscosity, 25C.'=77 cs.; color: 70 APHA.

EXAMPLE 4 Preparation of pentaerythritol monohydroxy monopelargonatedi(mercaptopropionate) A mixture of 148 grams technical pentaerythritol(containing 88 percent mono and 12 percent dipentaerythritol), 158 gramspelargonic acid and 212 grams mercaptopropionic acid was heated at 140C. in the presence of refluxing benzene until all water of condensationwas removed. Volatile components wereremoved under reduced pressure togive 449 grams of an oil product which contained 13.8 percent by weightmercaptan sulfur. Specific gravity at 25 C.=1.1360; viscosity at 250:302 cs.

EXAMPLE 5 Preparation of (pentaerythrito'l) (pelargonate)(mercaptopropionate 1,6

A 500 ml. flask equipped with thermometer and nitrogen sparge tube wascharged with 68.5 grams pentaerythritol,

158 grams pelargonic acid, 88 grams mercaptopropionic acid, 100 gramsbenzene. The mixture was refluxed at 95 to 150 C. for twelve hours.Benzene was removed under reduced pressure. A pale yellow oil productremained having a mercaptan sulfur content of 9.13 percent by weight.Specific gravity at 25 C.=1.140.

EXAMPLE 6 Preparation of poly(dibutyltin) (trimethylolpropanemonopelargonate dithioglycolate L The olymercaptoester of Example 1 (231grams) was heated with 124 grams of dibutyltin oxide at 100 C. in thepresence of refluxing benzene. After three hours time all water ofreaction had been removed. Benzene was removed under reduced pressure toleave 333 grams of a viscous yellow oil product. Specific gravity at 25C.=1.142. Tin content, calculated: 17.2 weight percent.

EXAMPLE 7 Preparation of poly(dibutyltin) [trimethylolpropanemonopelargonate di(thioglycolate)] (lauryl mercapho Polymercaptoester ofExample 1 (118 grams) was heated along with 124 grams of dibutyltinoxide and 103 grams of 2. C primary n-alkyl mercaptan for four hours at100 C. in the presence of refluxing benzene. Removal of water wascomplete after two hours. The mixture was filtered and benzene removedunder reduced pressure to leave a slightly viscous yellow residueproduct. Tin content: 17.3 weight percent, calculated.

EXAMPLE 8 Preparation of poly(dibutyltin) [pentaerythritolmonohydroxy-monopelargonate di(thioglycolate) (lauryl mercaptan) Aquantity of pentaerythritol monohydroxy monopelargonatedi(thioglycolate), (113 grams), was heated three hours at 100 C. alongwith 124 grams of dibutyltin oxide and 103 grams of a C primary n-alkylmercaptan in the presence of refluxing benzene. Removal of water ofreaction was complete after two hours. Filtration and removal of benzeneby heating under reduced pressure left a lightly viscous and yellowresidue product with specific gravity at 25 C. of 1.130 and tin contentof 18.2 percent by weight.

EXAMPLE 9 Preparation of poly dibutlytin) 2.0 [trimethylolpropanemonopelargonate di (thioglycolate) (lauryl thiogly- COlate 2 0 Aquantity of trimethylolpropane monopelargonate di- (thioglycolate), (118grams), was mixed with 124 grams of dibutyltin oxide and 133 grams oflauryl thioglycolate and heated at 100 C. for three hours in thepresence of refluxing benzene. Removal of water was complete after twohours reaction time. Removal of benzene by heating under reducedpressure left a yellow oil residue product with specific gravity at 25C. of 1.068. Tin content=17.2 percent by weight.

EXAMPLE 10 Preparation of poly(dibutyltin) [pentaerythritol monohydroxymonopelargonate di(thioglycolate)] (laury1 thioglycolate)Polymercaptoester from Example 2 113 grams) was mixed with 124 grams ofdibutyltin oxide and 133 grams lauryl thioglycolate and heated at l00 C.for three hours in the presence of refluxing benzene. Removal of waterwas complete after two hours. Benzene was removed by heating underreduced pressure and the product filtered to give a light yellow oilresidue product with a specific gravity at 25 C. of 1.140. Tincontent=l6.4 percent by weight, calculated.

8 EXAMPLE 11 Prepartion of poly(dibutyltin) [trimethylolpropanemonopelargonate di(mercaptopripionate) (lauryl thithioglycolate) Aquantity of trimethylolpropane monopelargonate di- (mercaptopropionate),(46.3 grams), was mixed with 49.6 grams of dibutyltin oxide and 53.4grams of lauryl thioglycolate and the whole heated for two hours at C.in the presence of refluxing benzene. Removal of water was completeafter one hour. Benzene was removed by heating under reduced pressure.Filtration left an oil product with viscosity at 25 C. of 363 cs.Specific gravity at 25 C.=1.040. Tin content=12.6 weight percent.

EXAMPLE 12 Preparation of poly(dibutyltin) [pentaerythritol monohydroxymonopelargonate di (mercaptopropionate) L0 (lauryl thioglycolate) Aquantity of pentaerythritol monohydroxy monopelargonatedi(mercaptopriopionate), (47.9 grams), was mixed with 49.6 grams ofdibutyltin oxide and 53.4 grams of lauryl thioglycolate and the wholeheated for 2.5 hours at 100. C. in the presence of refluxing benzene.Removal of water was complete after one hour. The product was filteredand benzene removed by heating under reduced pressure to leave a lightcolored oil. Viscosity at 25 C: 404 cs., specific gravity at 25 C.=1.10,tin content =17.2 weight percent (calculated=15.8 percent).

EXAMPLE 13 Preparation of poly dibutyltin) m [pentaerythritolmonohydroxy monopelargonate di (mercaptopropionate) (laurylthioglycolate m (toluene-2, 4-diisocyanate M In a separate experiment,42 grams of Example 12 product were combined with 3 grams toluenediisocyanate and heated in a nitrogen atmosphere at 100 C. for thirtyminutes. The product was a very viscous and pale yellow oil.

EXAMPLE 14 Preparation of poly(dibutyltin) [trimethylolpropanemonopelargonate di(mercaptopropionate) (isooctylthioglycolate)Pereparation of poly( dibutyltin) 5 [trimethylolpropane monopelargonatedi (mercaptopropionate) h A quantity of trimethylolpropanemonopelargonate di- (mercaptopropionate), (116 grams), was mixed with74.4 grams of dibutyltin oxide and heated at 100 C. for three hours inthe presence of refluxing benzene. Removal of water was complete afterone hour. The product was filtered and benzene removed by heating underreduced pressure. The residue product was viscous and slightly yellow.Tin content19.5 percent calculated.

EXAMPLE 16 Preparation of poly (dibutyltin 4 [trimethylolpropanemonopelargonate di (mercaptopropionate) (isooctylthioglycolate 2 Aquantity of trimethylolpropane monopelargonate di- (mercaptopropionate),(69.5 grams), was mixed with 49.6 grams of dibutyltin oxide, 21 grams ofisooctylthioglycolate and the whole heated at 100 C. for three hours inthe presence of refluxing benzene. Removal of water was complete after1.5 hours. Benzene was removed by heating under reduced pressure and theproduct filtered to give a viscous oil with specific gravity at 25 C. of1.181. Tin content=17.2 percent calculated.

EXAMPLE 17 Preparation of poly(dibutyltin) [trimethylolpropanemonopelargonate di(thioglycolate)] (lauryl thioglycolate) A quantity oftrimethylolpropane monopelargonate di(thioglycolate), (240 grams), wascombined with 248 grams of dibutyltin oxide, 267 grams of laurylthioglycolate and the mixture heated at 100 C. for 2.5 hours. Theproduct was filtered and benzene removed by heating under reducedpressure, leaving a viscous oil with specific gravity at 25 C. of 1.120.Tin content: 19.08 weight percent.

EXAMPLE 18 Preparation of poly(dibutyltin) [trimethylolpropanemonopelargonate di(thiog1ycolate) (isooctylthioglycolate) A quantity oftrimethylolpropane monopelargonate di(thioglycolate), (42.5 grams) wascombined with 49.5 grams dibutyltin oxide, 84 gramsisooctylthioglycolate and the mixture heated at 94 C. for four hours inthe presence of refluxing benzene. Removal of water was complete afterone hour. Filtration and removal of benzene by heating under reducedpressure left a very pale yellow oil. Tin content=13.6 weight percent,calculated. Specific gravity at 25 C.=1.100.

EXAMPLE 19 Preparation of poly(dibutyltin) [pentraerythritoldipelargonate di (thioglycolate) 1,0

A 500 ml. three-neck flask fitted with thermometer and nitrogen spargetube was charged with 68.5 grams pentaerythritol, 15 8 grams pelargonicacid, 83 grams thioglycolic acid, 100 ml. benzene and 0.5 gram methanesulfonic acid. The mixture was refluxed and water of condensationremoved for 9.5 hours at 95 to 150 C.

1 0 EXAMPLE 20 Preparation of poly(dibutyltin),,. [pentaerythritol(pelargonate) M (mercaptopropionate) A quantity of pentaerythritolpelarg0natc mercaptopr0pionate (100 grams), was combined with 35.4 gramsdibutyltin oxide and the mixture heated at 100 C. for 2.5 hours in thepresence of refluxing benzene. Water was removed as formed. Benzene wasremoved, after filtration, by heating under reduced pressures, to give aviscous oil product, specific gravity at 25 C.=1.140. Tin content=12.5percent (calculated).

EXAMPLE 21 Preparation of poly(dibutyltin) [pentaerythritol pelargonate)(mercaptopropionate) (isooctylthioglycolate) A quantity of(pentaerythritol) (pelargonateh (mercaptopropionate) (126 grams), wascombined with 95.7 grams dibutyltin oxide and the mixture heated at 100C., in the presence of refluxing benzene. Water was removed as formed.After five hours, the mixture was cooled, 81 grams ofisooctylthioglycolate were added and reflux at 100 C. continued for twohours. Benzene was removed by heating under reduced pressure and theresidue filtered to give a pale yellow product. Specific gravity at 25C.=1.090. Tin content=15.9 percent calculated.

In order to compare the stabilizing effectiveness of the mercaptidecondensation polymers of the present invention with a referencestabilizing material of the organotin type widely used in industry priorto this invention, oven tests of polyvinyl chloride resin stabilizedwith the various stabilizing compositions were conducted. Simple poly-(vinyl chloride) formulations containing polyvinyl chloride homopolymer,the stabilizer and mineral oil lubricant were premixed in a Hobart mixerand milled for five minutes at 325 F. on a two roll differential speedmill. The resin was then sheeted off and samples of the sheets werecompared in thermal stability by heating at 400 F. in a circulating airoven. Samples were removed for visual comparison at 10 minute intervals.Progressive thermal degradation was indicated by a progressive darkeningfrom a very slightly yellow color to black. The results of these oventests are set forth in Table I.

TABLE I Compound composition Example 1 Oven stability tests,

Parts minutes at 400 F.

Mineral PVC 2 oil 10 Reference 4 set fReffirs to the condensationpolymers produced in the several examples hereinbefore ort 2 Refers tosimple poly (vinyl chloride) homopolymer formulation used in the tests.

3 In the oven tests, degrees of thermal degradation have been evidencedby VSY=very slightly yellow, SY=slightly yellow, Y=yellow, and B=black.

4 The reference stabilizing composition used was dibutyltin-S,S-bis(isooctylthiogly colate) After cooling the flask, 132 grams ofdibutyltin oxide was EXAMPLE 22 Preparation of poly (dibutyltin 2.0(pentaerythritol pelarognate benzoate dithioglycolate)(isooctylthioglycolate) A reaction mixture containing 136 gramspentaerythrilow product. Calculated tin content is 11.9 weight percent.tol, 158 grams pelargonic acid, 122 grams benzoic acid and 233 gramsthioglycolic acid was heated at 135 C. in the presence of 0.5 gramp-toluene sulfonic acid catalyst and suflicient benzene to give refluxand eflicient removal of water formed during the reaction. After ninehours, all water of reaction was removed. Excess acids were removed byreduced pressure distillation and washing of the residue with aqueoussodium carbonate. Drying with vacuum and heat left a yellow oil withspecific gravity at 25 C of 1.178. Mercaptan sulfur content: 1.5.75weight percent.

A portion of this product (83 grams) was combined with 100 gramsdibutyltin oxide and 82 grams isooctylthioglycolate and the resultingmixture heated for two hours at 100 C. in the presence of refluxingbenzene. The product was filtered and benzene removed by heating underreduced pressure to give 254 grams of a light yellow oil with specificgravity at 25 C. of 1.1 86. Calculated tin content=18.2 weight percent.

EXAMPLE 23 Preparation of poly (dibutyltin) 1A (pentaerythritol) 1(pelargonate) (mercaptpropionate) 1 (isooctylthioglycolate) 0,8

A reaction mixture containing 148 grams pentaerythritol, 192.5 gramsmercaptopropionic acid and 27 6 .5 grams pelargonic acid was heated at185 C. in the presence of refluxing benzene. All water of reaction wasremoved. Volatiles were removed by nitrogen sparge and reduced pressureto leave 550 grams of a pale yellow oil containing 10.7 weight percentmercaptan sulfur.

A portion of this product (212 grams) was combined with 124 gramsdibutyltin oxide, 63 grams isooctylthioglycolate and heated for twohours at 100 C. in the presence of refluxing benzene. Removal of waterwas complete after one hour. Benzene was removed by heating underreduced pressure and the product filtered to give a viscous yellow oilwith viscosity at 25 of 858 cs. and specific gravity at 25 C. of 1.15.Calculated tin content-=15.1 weight percent.

EXAMPLE 24 Preparation of poly(dibutyltin) [trimethylolpropanepelargonate di thio glycol ate Lo phenoxyethylthioglycolate) 2D Amixture of 110 grams trimethylolpropane monopelargonatedi(thioglycolate), 124 grams dibutyltin oxide, and 105 gramsphenoxyethylthioglycolate 'was heated for three hours at 100 C. in thepresence of refluxing benzene. During this time, 9 ml. of water wasremoved from the reaction. Removal of benzene by means of reducedpressure and nitrogen purge left 338 grams of a viscous yellow oil withspecific gravity of 25 C. of 1,257. Calculated tin content-=17.8 weightpercent.

EXAMPLE 25 Preparation of poly(dibutyltin) t1-imethylolpropanepelargonate di (thioglycolate) (isoocty1thi0glycolate) A mixture of 125grams dibutyltin oxide, 110 grams trimethylolpropane monopelargonatedi(thioglycolate) and 102 grams isooctylthioglycolate was heated for twohours at 105 in the presence of refluxing benzene. During that time, 7ml. of water was removed from the reaction. Evaporation of benzene andfiltration of the residue left 328 grams of a pale yellow oil product.Calculated tin content=l8.l Weight percent.

EXAMPLE 26 Preparation of (pentaerythritol) (pelargonate)mercaptopropionate) 1 6 A three-liter flask equipped with thermometer,and nitrogen sparge tube was charged with 444 grams pentaerythritol, 596grams mercantopropionic acid, 950 grams pelargonic acid and 100 gramsbenzene. The flask was EXAMPLE 27 Preparation of poly(dibutyltin)[(pentaerythritol) pelargonate) 1,8 (mercaptopropionate)(phen0xyethylthioglycolate) 12 A mixture of 125 grams dibutyltin oxide,63 grams phenoxyethylthioglycolate and 230 grams polymercaptoester fromExample 26 was heated for two hours at 100 C. in the presence ofrefluxing benzene. During this time, 7 ml. of water was removed from thereaction. Evaporation of benzene solvent with nitrogen purge and reducedpressure and filtration left 410 grams of a yellow oil product withspecific gravity (25 C.) 1.179. Calculated tin content=14.3 weightpercent.

EXAMPLE 28 Preparation of poly(dibutyltin) [(pentaerythritoD(pelargonate) L (mercaptopropionate (n-dodecylmercaptide) 12 A mixtureof 125 grams dibutyltin oxide, 230 grams polymercaptoester from Example26 and 61 grams primary n-dodecyl mercaptain was heated for two hours atC. in the presence of refluxing benzene. During that time, 7 ml. ofwater was removed from the reaction. Evaporation of benzene andfiltration left 409 grams of a pale yellow product with specific gravity(25 C.) of 1.130 and viscosity (25 C.) of 1508 cs. Calculated tincontent-=14.4 weight percent.

EXAMPLE 29 Preparation of poly(dibutyltin) m [(pentaerythritol)(pelargonate) (mercaptopropionate) (n dodecyl mercaptide) A mixture ofgrams dibutyltin oxide, grams polymercaptoester from Example 26 and 105grams primary n-dodecyl mercaptan was heated for two hours at 100 C. inthe presence of refluxing benzene. During that time, 7 ml. of water wasremoved from the reaction. Evaporation of benzene and filtration left388 grams of a pale yellow oil having a specific gravity (25 C.) of1.082 and viscosity (25 C.) of 193 cs. Calculated tin content-=15.2weight percent.

EXAMPLE 3 0 Preparation of poly dibutyltin) M (pentaerythritol) 1,0

(pelargonate) (mercaptopropionate) (isoocty1- thioglycolate) 12 Amixture of 125 grams dibutyltin oxide, 230 grams polymercaptoester fromExample 26 and 63 grams isooctylthioglycolate was heated for two hoursat 100 C. in the presence of refluxing benzene. During that time, 7 ml.of water was removed from the reaction. Evaporation of benzene andfiltration of the residue left 405 grams of a pale yellow oil having aspecific gravity of 1.143 (at 25 C.) and viscosity (25 C.) of 982 cs.Calculated tin content: 14.6 weight percent.

EXAMPLE 31 Preparation of po1y(dibutyltin) (pentaerythritol) 1.0

(pelargonate) (mercaptopropionate) ,(phenoxyethylthioglycolate) m Amixture of 125 grams dibutyltin oxide, grams polymercaptoester fromExample 26 and 110 grams phenoxyethylthioglycolate was heated for threehours at 110 C. in the presence of refluxing benzene. During that time,8 ml. of water was removed from the reaction. Evaporation of benzene andfiltration of the residue left 399 grams of a pale yellow oil withspecific gravity (25 C.) of 1.206 and viscosity (25 C.) of 300 cs.Calculated tin content-15. weight percent.

The stabilizing compositions produced in Examples 22- 31 were subjectedto oven testing in a manner similar to the oven testing of the productsof Examples 6-21 as reported in Table I, except that the tests werecarried out at a temperature of 375 F. for a total period of 100minutes. In Table II'the results of these latter tests are tabulated anda number system is used to indicate color shadings resulting fromthermal degradation. Also the tin content of all samples, including thereference sample, is set forth 1'. L RJ.

(0 11') for comparison purposes.

TABLE II Compound composition Example 1 Parts Stabilizer Oven stabilitytests, minutes at 375 F. tin content, Mineral weight percent No. PartsPVC 2 oil 10 50 60 70 80 90 0 calculated 22 2 100 1. 5 0 1 1 2 2 2 318.2 2 100 1. 5 0 1 1 2 2 3 3 l5. 1 2 100 1. 5 0 1 1 2 2 2 3 17. 8 2100 1. 5 0 1 1 2 2 2 3 18. 1 2 100 1. 5 O 1 2 2 2 3 4 18. 6 2 100 1. 5 01 1 2 2 2+ 3 18. 2 2 100 1. 5 0 1 2 2+ 3 4+ 15. 1 2 100 1. 5 0 1 1 1+ 22+ 3 18. l 2 100 1. 5 0 1 1+ 2 2 3 4 14. 3 2 100 1. 5 0 2 2 2 2+ 3 4 14.4 2 100 1. 5 0 2 2 2 2+ 3 4 15. 2 2 100 1. 5 0 1 2 2 2+ 3 4 14. 6 2100 1. 5 0 1 1+ 2 2 2 3 18.6 2 100 0. 5 0 1 1 1+ 2 2 3 17. 8 2.65 100 0.5 0 1 1+ 2 2 3 14. 3 2. 5 100 0. 5 1 1+ 2 2 2 3 15.2 2. 100 0. 5 0 1 1+2 2 3 15. l 2 100 0. 5 0 1 1+ 2 2 3 3+ 15. l 2 100 0. 5 0 1 1+ 2 2 3 3+18.6 2 100 0. 5 1+ 1+ 2 2 3+ 5 14. 3 2 100 0. 5 l 1 2 3 4 5 14.. 4 2 1000. 5 1 1+ 1+ 2 2 3+ 5 15. 2 31.. 2 100 0. 5 0 1 1 2 2 3 4 15. 1Reference 2 100 0. 5 0 1 1 2 2 3 4 18. 6

1 Refers to the condensation polymers produced in the several exampleshereinbefore set forth. 2 Refers to simple poly(vinyl chloride)homopolymer formulation used in the tests.

3 Numbers represent increasing color: 0=eolorless, 1=first noticeableyellow, 5=black.

4 The reierence stabilizing composition used was dibutyltin-S,S-b1s(lsooctylthioglycolate).

From the tabulated data in Tables I and II, it will be apparent that thestabilizing compositions of the present invention are highly effectivein their thermal stabilizing properties for polyhaloresins. Aspreviously indicated, the processing characteristics, such as fusiontime and lubricity, of the stabilized polyvinyl chloride formulationscan be controlled and selectively varied by varying the struc ture ofthe stabilizer additive. This selective variation of processingcharacteristics, however, has been found to be independent of the tincontent of the formulations.

The stabilizing compositions of the invention can be utilized in awidely varying range of concentration in the stabilization of resinsderived from polyvinyl halide resins, such range embracing from about0.1 weight percent to about 10 weight percent. While this range isoperative in the case of the polyvinyl halide resins, it is herepreferable to use the stabilizers in concentrations of from about 0.5weight percent to about 5 weight percent, and most preferably from about1.5 to about 3 weight percent.

In addition to the incorporation of the stabilizing compounds of theinvention in resinous formulations of the type described, theseformulations may also contain conventional plasticizer materials, suchas phthalates, adipates and epoxy esters, lubricants such as calciumstearate, hydrocarbon waxes, polyethylene synthetic diamide based waxes,pigments and colorants as well as processing or impact modifiers such asABS resins, acrylates, chlorinated polyethylenes, hydrocarbon resins,etc.

Although certain specific embodiments and examples of the invention havebeen described herein in order to wherein X is an alkylene-substitutedacyl radical in which alkylene contains from 1 to 6 carbon atoms, Y is asaturated aliphatic hydrocarbon radical containing from 3 to 11 carbonatoms, m is a whole number greater than 1, n is a number from 1 to 6, Ris alkyl of 4 to 8 carbon atoms, R is selected from the group consistingof hydrogen and an acyl radical derived from an organic acid selectedfrom the group consisting of a saturated aliphatic monocarboxylic acidand an aromatic monocarboxylic acid, and R" is the residue formed by theremoval of acidic hydrogen from a member selected from the groupconsisting of an alkyl mercaptan, a mercaptoalkanoic acid, amercaptoalkanoic acid ester, an aliphatic monocarboxylic acid, and anaromatic monocarboxylic acid.

2. A heat stable vinyl halide resin composition containing from about0.1 to about 10 weight percent of the composition defined in claim 1.

3. The composition of claim 1 wherein the stabilizer is poly(dibutyltin)(pentaerythritol pelargonate benzoate dithioglycolate)(isooctylthioglycolate) the numerals indicating molar proportions.

4. The composition of claim 1 wherein the stabilizer is poly(dibuty1tin)[(pentaerythritoh (pelargonate m (mercaptopropionate) 1.1(phenoxyethylmercaptopropionateh the numerals indicating molarproportions.

5. The composition of claim 1 wherein the stabilizer 15 ispoly(dibutyltin) [(pentaerythritoD (pelargonate) (mercaptopropionate)L14 (n-dodecylmercaptideh the numeral indicating molar proportions.

6. The composition of claim 1 wherein the stabilizer is poly(dibuty1tin)trimcthylolpropane pelargonate di(thioglycolate)](phenoxyethylthioglycolate) the numeral indicating molar proportions.

7. A composition of matter according to claim 1 Wherein R" consists of amercaptoester radical produced by the esterification of amercaptoalkanoic acid and a monfunctional alcohol.

8. A composition of matter according to claim 7 wherein themercaptoalkanoic acid is mercaptopropionic acid and the monofunctionalalcohol is selected from the group comprising isooctanol andphenoxyethanol.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 11/1964 France.

4/1966 Great Britain.

DONALD E. CZAJA, Primary Examiner V. P. HOKE, Assistant Examiner US. Cl.X.R.

